1. Field of the Invention
The present general inventive concept relates to a buffer amplifier and a method of generating driving voltages using the same and, more particularly, to a buffer amplifier included in a display driver and a method of generating a driving voltage using the same.
2. Description of the Related Art
As a gradation representation performance of a display system is improved, a display driver of the display system must apply a precise driving voltage to a display panel. That is, the display driver must generate a more accurate driving voltage as a number of gray scales increases.
FIG. 1 illustrates a conventional display device. Referring to FIG. 1, the display device includes a display panel 100, a source driver 110 and a gate driver 120. The display panel 100 includes a plurality of gate lines GL1, GL2, . . . and a plurality of source lines S_1, S_2, S_3, . . . . The gate lines GL1, GL2, . . . are driven by the gate driver 120 and the source lines S_1, S_2, S_3, . . . are driven by the source driver 110. The source driver 110 includes a plurality of decoders DEC1, DEC2, DEC3, . . . and a plurality of buffers BUF1, BUF2, BUF3, . . . .
The decoders DEC1, DEC2, DEC3, . . . respectively convert display data signals D1, D2, D3, . . . into gradation voltages V1, V2, V3, . . . . The buffers BUF1, BUF2, BUF3, . . . respectively buffer the gradation voltages V1, V2, V3, . . . to generate driving voltages Vo1, Vo2, Vo3, . . . . The driving voltages Vo1, Vo2, Vo3, . . . are respectively applied to the source lines S_l, S_2, S_3, . . . .
For example, the display data D1 is converted into the gradation voltage V1 by the decoder DEC1, the gradation voltage V1 is buffered by the buffer BUF1, and the driving voltage Vo1 generated according to a buffering operation of the buffer BUF1 is applied to the source line S_1. The buffer BUF1 has a respective offset characteristic thereof, and thus a deviation exists between an output voltage (that is, the driving voltage Vo1) and an input voltage (that is, the gradation voltage V1) of the buffer BUF1. That is, the output voltage (that is, the driving voltage Vo1) of the buffer BUF1 includes a positive deviation or a negative deviation. Furthermore, the buffers BUF2 and BUF3 have respective offset characteristics thereof and the driving voltages Vo2 and Vo3 generated by the buffers BUF2 and BUF3 include a positive deviation or a negative deviation.
Moreover, the buffers BUF1, BUF2, BUF3, . . . have different offset characteristics, and thus the buffers BUF1, BUF2, BUF3, . . . have different deviation polarities and deviation sizes. Accordingly, the driving voltages Vo1, Vo2, Vo3, . . . respectively generated by the buffers BUF1, BUF2, BUF3, . . . have different levels even though a same gradation voltage is applied to the buffers BUF1, BUF2, BUF3, . . . . Furthermore, when the driving voltages Vo1, Vo2, Vo3, . . . are generated with a large dispersion range of deviations, display quality and gradation representation performance of the display device decrease.